Process of recovering sulfur dioxid



W. H. HOWARD.

PROCESS OF RECOVERING SULFUR DIOXID.

I APPLICATION FILED MAYIO, 1918.

1,377,012. Patented M3173, 1921.

wazwzi A TTORNEYS rarrala'r OFFICE.

WILLIAM H. HOWARD, or SALT LAKE CITY, UTAH, ASSIGNOR '.[0 AMERICAN SMELTING AND REFINING COMPANY, OF NEW YORK, N. Y., A CORPOBA.

TION OF NEW JERSEY.

PROCESS OF RECOVEBING SULFUR DIOXID.

Specification of Letters Patent.

Application filed May 10, 1918. Serial No. 233,640.

,from the waste gases incident to blowing copper matte in a converter.

Sulfur dioxid has heretofore been recovered as a by-product incident to other metallurgical operations and processes, but in attempting to apply the same processes to waste gases from acopper converter difficulties have been encountered, particularly in that the cost of the sulfur dioxid was too high. This is due in part to the fact that in converting copper the matte ordinarily contains a relatively high percentage of iron and a small percentage of miscellaneous impurities, in addition to the copper and sulfur, and therefore, in the early stages of the blowing, the air acts on the iron and other impurities as well as on the sulfur, and therefore,the gases are so low in sulfur dioxid that the quantity ofwater required to absorb the sulfur dioxid makes the process expensive.

It has been proposed to utilize the heat of the converter gases for generating steam in boilers, but here again difliculties have been encountered, because in the early stages while the iron and miscellaneous impurities are coming off, the gases carry flue dust,

ejected sla and fume, which have an objectionable e ect on the boiler operations.

Generally speaking, the copper matte in the first stages of the converting process may contain approximately forty (40) per cent. of copper, thirty (30) per cent. of iron, twenty-five (25) per cent. of sulfur, and five (5 per cent. of miscellaneous impurities. t this stage the converter gas might contain perhaps as high as fourteen (14) per cent. of sulfur dioxid, but as a practical matter, due to leakages around the hood caused by frequent breaking of the hood connections, the percentage is considerably lower, not averaging over seven (7) per cent. of sulfur dioxid.

After the process'has been carried on until the matte has reached a stage where it 1s commonly known as white metal, it may conta1n approximately seventy-five -(7 5) per cent. of copper, and the balance almost all sulfur. At this stage the converter gas mlght run in the neighborhood of twentyone (21) per cent. of sulfur dioxid. At this stage of the operation the hood connections are not broken, but the connection cannot be made perfectly tight, and therefore there is some leakage, so that in practice this percentage might be reduced as low as fifteen (15) per cent. 1

It will be seen, therefore, that a recovery process applied to a single converter would be acting on a gas, the composition and character of which is variable, or if the process was used only when the gas was in a satisfactory condition, the process would be intermittent and the heat from the gases could not be used in boilers.

To overcome these objections I have devised a system whereby the matte is treated in one set of converters until it reaches the stage where the converter gas is of a character to permit the profitable recovery of the sulfur dioxid, or in other words, until the matte has reached the stage where it is commonly known as white metal. This white metal is then removed to a separate converter, or preferably a pair of converters, and the recovery process is then carried on.

Patented May 3, 1921.

In the accompanying drawing, I have shown diagrammatically a pair of converters in which the white metal is treated, and the heat of the converter gases used under a pair of boilers for the purpose of reducing the cost of recovery.

The converters- 1 and 11 are of the usual rotary type, and discharge their gases through flues 2 and 12, provided with dampers 3 and 13, respectively. These converters are used alternately, so that while one is blowingthe other is being emptied and recharged. The flues from the converters join in acommon passage 4, and by means of the dampers 3 and 13 a continuous flow of converter gas may be maintained through the common passage 4. From this common passage 4 lead flues 5, provided with dampers 6, to one or moreboilers 7. It is desirable to use at least two boilers because if it is necessary to clean. or repair a, boilerit without stopping the operation of the converters.

' After the converter gas passes through the boilers 7, and its heat is there utilized to the desired extent, it passes into the flue 9,

where it goes on to be treated in the'usual manner for the recovery of the sulfur dioxid. This process of recovery is well known and need not be described.

By this means I obtain a steady flow of converter gas containing no objectionable impurities to prevent its use in boilers, and the converter gas is high enough in sulfur dioxid to make the recovery process more profitable. The steam from the boilers may e used in the later stage of the recovery process.

By separating the convertingprocess into separate stages and at the same time definitely controlling one of these stages to-produce a redetermined volume of gas within a practically definite time by using a fixed quantity of material of a uniform composition, I have been enabled to eliminate the difficulties which have heretofore attended the recovery of sulfur dioxid from the waste gases in this class of metallurgical opera: tions. By my improved process the losses resulting from the handling of large quantities of waste gases which are low in their carbon dioxid content is avoided, and on the other hand, a constant volume of gas which has a relatively high and profitable sulfur dioxogen content is obtained. Consequently the extraction of the sulfur di-' ({Xld Cfll'l be carried on in subsequent operations with a unlform and constant supp1y of 'gas according to a definite plan and result? ing in a minimum outlay for apparatus and for operation.

Having described my invention, what I claim is Y 1. The process of-recovering sulfur dioxid from copper matte, which consists in treat- 4 ing a relatively low sulfurdioxid content,

then removing portions of the matte and successively blowing such portions for predetermined periods of time to maintain a continuous fiow'of gas having a relatively hi h sulfur dioxid content and free from so id impurities.

2. .The process of recovering sulfur dioxid from copper ores, which consists in treating ores to reduce the same to matte, then treating said matte in a plurality of converters to produce White metal, removing said matte in predetermined quantities at intervals, from each of said converters and subjecting such removed portions successively to an air blast for predetermined periods of time re- (111126; to maintaltin a ponltinuous flow of gas con almn a re ative i hercenta e of sulfur dio ggid, y P

3. The process of recovering sulfur dioxid from copper matte, which'consists in treat-- ing the matte in a plurality of converters to obtain a supply of white metal, successively removing portions of said white metal from the converters at intervals, subje ting said removed portions successively .to intense heat tomaintain a continuous flow. of gas having a substantially uniform sulfur. dioxid content and continuously collecting said sulfur dioxid.

4. The process of recovering sulfur dioxid from copper matte, which consists in heating the matte to form white metal, successively removing portions of said u hite metal at regular intervals, heating each of sa1-:l portions for a predetermined time to maintain a continuous supply of gas having a relatively'high percentage of sulfur dioxid and continuously collecting said sulfur dioxid.

5. The process of recovering a constant supply of sulfur dioxid from converter gases, which consists in treating copper matte to produce white metal, successively removing a suflicient quantity of said white metal to give off a predetermined quantity of sulfur dioxid, and successively treating said portions of white metal for predetermined periods to maintain a constant supply of gas of approximately uniform composition. v Y

6. The process of recovering a constant supply of sulfur dioxid from converter gases, which consist in treating the matte to form white metal, then successively removing predetermined portions of white metal and treating the same to maintain a flow of gas of substantially constant volume containing a relatively high percentage of sulfur dioxid.

' 7. The process of providing a constant supply of sulfur dioxid from converter gases, which consists in blowing co per.

matte until the gases produced there rom have apredetermined composition, then removing portions of "the matte, successively heating and blowing said portions to maintain a steady flow of gas of substantially constant volume, collecting said gases, andremoving the sulfur dioxid.

8. The process of recovering sulfur dioxid from copper matte, which. consists in blowing the matte until the gas produced therefrom has a predetermined composition, then removing the matte to'a plurality of con- ,verters, treating the matte in each converter alternately for approximately an equal period of time whereby a continuous flow 0 gas is obtained of substantially uniform composition.

9. The process of recovering sulfur dioxid. from copper matte, which consists in collecting the gases from a plurality of con- Wrters, supplymg each converter alternately with matte adapted to produce a gas having a predetermined composition and treating the matte in each converter for approximately equal periods of time whereby 'a continuous flow of gas may be obtained of substantially uniform composition.

10. The process of recovering sulfur dioxid from waste gases from copper matte converters which consists in treating the matte in one set of converters until substan tially all of the impurities except sulfur have been removed, then removing the residual matte to another set of converters, successively treating the residual matte in each converter of said second set of converters for a predetermined time to maintain a constant supply of gas, passing the resultant gas through a boiler to utilize the heat, and then treating the gas to extract the sulfur dioxid.

11. The process of recovering sulfur dioxid from waste gases from copper matte converters which consists in treating the composition,

matte in one set of converters until it becomes white metal, then removing the residual matte to another set of converters and treating the same to obtain a continuous flow of gas of substantially uniform passing the resultant gas through a boiler to utilize the heat, and then treating the gas to extract sulfur dioxid.

12. The process of recovering sulfur dioxid from a pair of blocks of a sulfur containing substance such as copper matte, which consists in treating the substance to drive off gases having a relatively low sulfur dioxid content, blowing first one and then the other block to maintain a continuous flow of gas having a relatively high sulfur dioxid content and collecting said high grade sulfur dioxid gas.

Signed at New York city, in the county of New York and State of New York, this 4th day of May, A. D. 1918.

' WILL H. HOWARD. 

